Sometimes your diesel engine emits unwanted noise. This can be frustrating, especially if you’re not sure what is the cause.
In other articles, we’ve talked about diesel engine noise when the engine is under load, belt noise and valve train noise.
In this post, we’re looking at noise during clutch engagement and how to diagnose some of the possible causes.
What’s Going On During Clutch Engagement?
To properly diagnose unwanted noise during clutch engagement, it helps to understand what clutch engagement actually is.
Clutch engagement is when the truck operator pushes the clutch pedal, selects a lower gear, and then lifts their foot to get the vehicle rolling.
This puts a lot of stress and strain on the vehicle as you get something from a still state to a rolling or moving one. It involves a lot of energy, or, as is true in this situation, horsepower.
And, while you’re trying to get tons of weight moving from a standstill, you can get a lot of twisting or bending happening.
What Can Stress During Clutch Engagement Do To Your Engine?
During this event, the stress is actually on the frame rails as it tries to support the engine and keep it in position (upright and forward). At the same time, it has to pull the heavy load attached to it.
Because of the turning crankshaft, there’s an adverse effect on the material it’s turning within.
Your crankshaft turns within a block, and as it rotates, it wants to twist the block as well. Because this is fastened to the frame rails, it’s actually trying to twist the entire vehicle to the side.
Causes of Noise During Clutch Engagement
Several things could be the cause of the noise you’re hearing during clutch engagement, including a broken engine mount and leaking gaskets.
Broken Engine Mount
In a normally functioning vehicle, the engine would stay where it’s supposed to in the frame rail because the mount holds it there.
If the mount is broken, though, the engine will actually lift up and twist in the frame. This can cause the engine to hit other parts under the hood, like the piping and air cleaners
Diagnosing this problem usually takes two people. Somebody will need to be in the vehicle with the brakes set so that it can’t move.
In some cases, you’ll actually be able to see the engine turning. There’s a limit to how much it can twist, and if it’s twisting too much, or if it lifts up and drops down, you probably have a broken mount.
Sometimes it can even come up high enough to hit the hood and puncture it.
If the mount is broken, it’s a fairly straightforward fix. You just need to replace the mount.
Then, you’ll need to check and ensure you no longer have any unwanted noise.
Leaking Gaskets
If you aren’t seeing your engine lift, though, the problem might be coming from leaking gaskets. This can sound more like chirping, clicking or knocking.
This might be caused by a failure in the gasket between the cylinder head and exhaust manifold. The exhaust will then come through the failed gasket and make a noise, usually like a sharp whistle, although in some cases it has sounded more like a tick or a knock, depending on how the gasket failed.
The same thing can happen when the head gasket fails. When the exhaust stroke happens, you’ll hear a noise as it exits where it shouldn’t be.
HHP is Here To Help!
If you’re experiencing unwanted engine noise, we can help!
We have a wide selection of parts for a large number of diesel engine applications. We can make sure you’re getting the parts you need to get back up and running.
Our ASE Certified Staff can answer your questions and provide diagnostic assistance, so you can be confident in the parts you’re buying.
It’s our mission to take the risk out of buying diesel engine parts.
From diagnosis through delivery, we’re Highway & Heavy Parts!
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